Unable to build world. multiple symptoms

[Tom Parquette]

I updated my 5.0-CURRENT sources yesterday (Saturday morning) and ran my 
buildworld script.
When the compiles failed, I searched the mailing lists and found someone 
else having the same problem.
His solution was to change the -j value (I was running with -j10 on my 
dual processor AMD). 
I have tried all the way down to -j1 and the compiles still fail.  I 
took the -j value out completely and it still fails. 
Running without the -j value at all got me the error message #error 
FreeBSD alloca support needed for this compiler from 
/usr/obj/usr/src/i386/usr/include/sys/cdefs.h:

I cannot find any response in the archive to either Email.

I saved tails of some of the failing compiles with various -j values if 
someone wants to see them.
TIA for any help.
Cheers...